The invention relates to a method for the purification and recirculation of gases which are fed to a process plant, preferably a plant for the production of metal powder or a plant for compacting metal powder under elevated pressure.
The gases exiting the plant are at a reduced pressure and are conveyed in a closed loop of filters and pressurizing means for the mechanical and/or chemical purfication of the gases as well as for repressurization. In addition, the invention relates to an apparatus suitable for carrying out this method. Adsorbers and reactors for the mechanical and chemical purification of the gases may be provided as filters.
U.S. Pat. No. 4,629,407 discloses a plant for the production of metal powder which is equipped with a gas recycling system. In order to raise the purified gases to the required pressure for atomizing the metal powder (between 8 and 160 bar), a multi-stage compressor is required. The cost for this compressor is quite high as far as investment and operating costs are concerned, especially if the gases to be purified and recirculated must be brought to pressures which exceed 40 bar.